The present invention relates to structural systems. More particularly, the present invention relates to modular systems for constructing tubular structures.
Certain permanent and semi-permanent free-standing frame members require systems that can be readily assembled and disassembled. The frame members are required to provide a durable and stable structure, be easy to handle and be installable by limited number of persons. The frame members can form a wide variety of shelter frames such as outdoor tents, circus tents, playground equipment, geodesic domes, greenhouses, swimming pool structures, etc. The frame members can also form internal structures, such as furniture, stands, shelving, etc.
One problem with many systems is that telescoping members are required to assemble and disassemble a structure. The telescoping members are costly, complicated and tend to make the structure less rigid or strong. Some systems, for instance, require inner and outer spring loaded tubes and a bolt or clamp that tightens the members together to form a member having a desired length. Other systems require an internal threaded rod or ball screw and an internally threaded member that threads onto the ball screw. When the threaded member is turned, the length of the member shortens or lengthens. Still other systems require a plurality of internal rods having threaded ends connected by a right angle gear and a second mating gear that couples to a handle, which extends outside of the member to enable an operator to turn the handle and thereby turn the rods to lengthen or shorten the member.
Obviously, each of the above systems is more complicated, costly, and heavy than simply using a section of tube. In order to put together and take apart the above systems, the members need to be adjustable. A need therefore exists for a system that allows a structure to be assembled and disassembled without having to move a tubing member along its centerline. The system should optimally take advantage of the relatively low cost and structural stability provided by off the shelf tubing.
There are known systems for releasably interconnecting frames that do not require telescoping. These systems have typically used screw connectors or quick disconnects, which have a number of drawbacks. First, in some systems the connectors or quick disconnects are formed integrally as part of the frame member. Here, the length of the frame members must be carefully machined, which adds to the expense of manufacture. Second, the integral connectors often require more than one person for assembly. Third, many of the connectors are limited to providing only right-angle connections. Such connectors obviously limit the shape and flexibility of the resulting structures.
A need therefore further exists for a system that has non-integral connectors, which do not require precise and expensive machining and tolerances. Further, the system should allow for members to be connected at multiple angles and for curved members.
The present invention provides an improved modular system for constructing a tubular structure. More specifically, the improved system allows the structural tubing to be assembled and disassembled in a direction perpendicular to a centerline of the tubing without having to move the tubing along its centerline. The improved structural system includes various features and components that allow the structural tubing to be positioned at various angles. The system also enables curved tubing to be used. The present invention therefore provides a flexible, easy to use, light-weight, low-cost and sturdy system that may be adapted to build a multitude of different structures, such as industrial and architectural railings, fencing, shelter frames for outdoor tents, circus tents, playground equipment, geodesic domes, greenhouses, swimming pool structures, etc. The frame members can also form internal structures such as furniture, stands, shelving.
In one preferred embodiment, the structural tubing system includes a hub and at least one connector that removably couples to the hub. The connector has a first end that couples to the hub and a second that defines a notch. One of the walls of the notch removably connects to a flange that extends radially in one or two directions from the centerline of the connector. The connector and the flange removably couple to one end of an adapter, which itself contains a mating notch. The connector and the adapter thereby sandwich the flange. The combined open space of the notches in one preferred embodiment equals the diameter (if circular tubing) or cross-sectional distance (if square or rectangular tubing) of the tubing less the thickness of the internal flange. This creates a uniform diameter or cross-sectional distance across mating pieces of the present invention.
The second end of the adapter is sized and shaped to receive a length of tubing. The flange that extends in either direction from the connector can in turn couple to additional tube receiving adapters. In this way, when multiple connectors are removably connected to the hub, virtually any type of shape can emanate from the hub. The hub, connector, flange and adapter may be modified in a variety of ways as described below to create specialized fittings for specific application, e.g., for curved tubing assemblies or portions of assemblies.
The notch enables an operator to readily bolt and unbolt the adapters and tubes to the connectors and hubs. This way, the operator can translate the adapters and tubes to and from the connectors, flanges and hubs in a direction perpendicular to the centerline of the connector, adapter and tube. A single operator can therefore construct a structure using the modular system of the present invention.
The structures of the present invention are adaptable to be rectilinear or curvilinear and have cross-bracing in three rectilinear and two diagonal planes. The structures are adaptable to be made from standard round, square or rectangular tubing or pipe. The tubing may be aluminum, steel, stainless steel (underwater applications), wood or plastic. The tubing may be any size, e.g., xc2xe inch to 4 inches (2 cm to 10.2 cm). The hub, connectors, adapters and tubing are held together by screws and welding for metal and plastic and by dowels biscuits and glue for wood.
It is therefore an advantage of the present invention to provide a modular structure system that is easy to use.
Further, it is an advantage of the present invention to provide a modular structure system that does not require telescoping members.
Moreover, it is an advantage of the present invention to provide a modular structure system that is readily assembled and disassembled.
It is another advantage of the present invention to provide a modular structure system that is light-weight.
It is a further advantage of the present invention to provide a modular structure system that is adaptable to be made of many different types of materials.
It is still another advantage of the present invention to provide a modular structure system that is low-cost.
It is still a further advantage of the present invention to provide a modular structure system that is sturdy.
Still further, it is an advantage of the present invention to provide a modular structure system that may be used to construct a variety of two dimensional and three dimensional structures.
Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description of the Invention and the figures.